1. Field of the Invention
The invention relates to the topical treatment of acne. Acne is a common inflammatory disease involving sebaceous glands. Acne generally appears in early adolescence, affecting more than 80% of teenagers. The severity of the inflammation varies. It is characterized, in order of increasing severity, by comedones, pustules, papules, inflamed nodules, infected cysts, and, in extreme cases, canalizing inflamed and infected sacs.
Corynebacterium acnes and Staphylococcus aureus, normally found in the flora of the skin, have been implicated as contributing agents in the more inflammatory types of acne. It is believed that C. acnes splits the triglycerides in the sebum, thereby liberating free fatty acids and causing the inflammation of acne.
The currently accepted name for Corynebacterium acnes, Propionibacterium acnes, will be used in the specification in discussions of the activity of antibiotic A-201A.
2. The Prior Art
A variety of treatments have been used for acne. Topical antibacterials, such as hexachlorophene, retinoic acid and corticosteroid lotions, with or without neomycin, have been used with moderate success. Systemic administration of broad-spectrum antibiotics, such as tetracycline and clindamycin, may improve severe acne, but the risk of side effects is great. Neither systemic antibiotic therapy nor topical treatments have, therefore, been satisfactory remedies for acne.
Generally, antibiotics have not been used in the topical treatment of acne. Exceptions include the use of neomycin, erythromycin, and antibiotics of the lincomycin family, such as clindamycin (U.S. Pat. No. 3,969,516). We have now discovered that antibiotic A-201A is an effective agent for the topical treatment of acne. Antibiotic A-201A is described by Hamill et al. in U.S. Pat. No. 3,843,784. The structure of A-201A has been determined by H. A. Kirst et al., (ICAAC Meeting, Chicago, Ill., October, 1976) to be as follows: ##STR1##